MEDIUM CONTRAST RECORDING APPARATUS

PURPOSE:To prevent the variation of the recording density of the same gradation level, by correcting various factors of environmental temp. and heat accumulation to obtain the number of pulses or pulse width corresponding to a gradation level signal. CONSTITUTION:A gradation level signal is inputted to a judge means 2 through a gradation level signal input terminal 1. The judge means 2 is provided in order to judge whether the gradation level signal is equal to or more than a reference value and inputs the data of '1' to a counting means 4 when said signal is equal to or more than the reference value outputted from a reference level generator 3 and inputs the data of '0' to said means 4 when the gradation level signal is below said reference value. The counting means 4 counts the output of the judge means to output the 4-bit heat accumulation data corresponding to the counting result to a pulse generator 5. The pulse generator 5 outputs the number of pulses corresponding to the gradation level signal inputted according to the above-mentioned heat accumulation data to control a thermal head 6. A table showing the relation of the gradation level signal, the heat accumulation data and the number of pulses is prepared for the pulse generator 5.